Commit f6f66c1b authored by Kees Cook's avatar Kees Cook Committed by Linus Torvalds

lib/test_bitmap.c: do not accidentally use stack VLA

This avoids an accidental stack VLA (since the compiler thinks the value
of "len" can change, even when marked "const").  This just replaces it
with a #define so it will DTRT.

Seen with -Wvla.  Fixed as part of the directive to remove all VLAs from
the kernel: https://lkml.org/lkml/2018/3/7/621

Link: http://lkml.kernel.org/r/20180307212555.GA17927@beastSigned-off-by: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Cc: Yury Norov <ynorov@caviumnetworks.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5f00ae0d
......@@ -296,15 +296,17 @@ static void __init test_bitmap_parselist(void)
}
}
#define EXP_BYTES (sizeof(exp) * 8)
static void __init test_bitmap_arr32(void)
{
unsigned int nbits, next_bit, len = sizeof(exp) * 8;
unsigned int nbits, next_bit;
u32 arr[sizeof(exp) / 4];
DECLARE_BITMAP(bmap2, len);
DECLARE_BITMAP(bmap2, EXP_BYTES);
memset(arr, 0xa5, sizeof(arr));
for (nbits = 0; nbits < len; ++nbits) {
for (nbits = 0; nbits < EXP_BYTES; ++nbits) {
bitmap_to_arr32(arr, exp, nbits);
bitmap_from_arr32(bmap2, arr, nbits);
expect_eq_bitmap(bmap2, exp, nbits);
......@@ -316,7 +318,7 @@ static void __init test_bitmap_arr32(void)
" tail is not safely cleared: %d\n",
nbits, next_bit);
if (nbits < len - 32)
if (nbits < EXP_BYTES - 32)
expect_eq_uint(arr[DIV_ROUND_UP(nbits, 32)],
0xa5a5a5a5);
}
......
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